Electrochemical recognition of tryptophan enantiomers based on the self-assembly of polyethyleneimine and chiral peptides

Electrochemical chiral interface based on achiral polyethyleneimine (PEI) and chiral peptide (D-BGAc) was constructed using self-assembly technology and used for electrochemical recognition of tryptophan (Trp) enantiomers via differential pulse voltammetry (DPV). Under optimized experimental conditions, the oxidation peak current ratio of D-Trp to L-Trp (ID/IL) was observed to be 3.4 using PEI/D-BGAc/GCE (glass carbon electrode). More interestingly, the PEI/D-BGAc chiral interface exhibited chiral recognition of D- and L-Trp via contact angle measurements. In addition, there was a good linear relationship between the peak current and Trp enantiomer concentration in the range of 0.002–0.15 mM. Finally, the PEI/D-BGAc/GCE system can be used to quickly determine the ratio of isomers in Trp racemic solution, which is of great significance for the chiral recognition in racemic mixtures of chiral compounds. Meanwhile, the PEI/D-BGAc/GCE showed good stability and reproducibility.